Hypersoninc flows in non-equilibrium

The numerical tools are developed based on previous in-house codes for high-speed simulations with improvements in both numerical and physical modeling. Additionally, a modular, open-source library is coupled with the flow solver for modeling real-gas effects in variable atmospheric mixtures. Verification against literature is done for canonical flat-plate boundary layers with various choices for gas modeling, with excellent agreement observed in all cases. The implementation of an artificial-diffusivity shock-capturing numerical scheme is then verified for supersonic shockwave–boundary-layer interaction (SBLI) cases and the improved code’s capabilities are demonstrated for the cases of hypersonic SBLI and a sonic jet injection in a hypersonic crossflow, at higher enthalpy levels than those previously investigated. The results show excellent agreement with previous observations in the literature. The work presented in this paper demonstrates the range of applications that can be investigated with this tool, highlights the need for accurate physicochemical modeling, and paves the way for addressing increasingly more complex configurations and flows.

Interfacial flows with phase-change

The treatment of complex geometries in Computational Fluid Dynamics applications is a challenging endeavor, which immersed boundary and cut-cell techniques can significantly simplify by alleviating the meshing process required by body-fitted meshes. These methods however introduce new challenges, as the formulation of accurate and well-posed discrete operators becomes nontrivial. Here, a conservative cartesian cut cell method is proposed for the solution of the incompressible Navier–Stokes equation on staggered Cartesian grids. Emphasis is set on the structure of the discrete operators, designed to mimic the properties of the continuous ones while retaining a nearest-neighbor stencil. For convective transport, a divergence is proposed and shown to also be skew-symmetric as long as the divergence-free condition is satisfied, ensuring mass, momentum and kinetic energy conservation (the latter in the inviscid limit). For viscous transport, conservative and symmetric operators are proposed for Dirichlet boundary conditions. Symmetry ensures the existence of a sink term (viscous dissipation) in the discrete kinetic energy budget, which is beneficial for stability. The cut-cell discretization possesses the much desired summation-by-parts (SBP) properties. In addition, it is fully conservative, mathematically provably stable and supports arbitrary geometries. The accuracy and robustness of the method are then demonstrated with flows past a circular cylinder and an airfoil.